Question

I have a need to be able to issue “create trigger” over DBI. I can’t seem to get the delimiter command working. Can anyone find a way to make this work?

Code:

use strict;
use DBI;
my $dbargs = {mysql_auto_reconnect => 1,
              AutoCommit           => 0,
              RaiseError           => 1,
              ShowErrorStatement   => 1}; 

my $dsn = "DBI:mysql:database=xdisp;host=cycldev06";
my $dbh = DBI->connect( $dsn, 'sqluser', '', $dbargs);

my $sql = qq{ 
    DELIMITER // 
        CREATE TRIGGER `hardware_last_status` BEFORE UPDATE
            ON `hardware` FOR EACH ROW BEGIN
                                IF NEW.status != OLD.status AND NEW.last_status = OLD.last_status THEN
                                    SET NEW.last_status = OLD.status;
                                END IF;
                            END
            //
};

$dbh->do($sql);

Results:

DBD::mysql::db do failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER // 
        CREATE TRIGGER `hardware_last_status` BEFORE UPDATE
      ' at line 1 at test.pl line 24.

and that SQL works fine at the MySQL command line.

Answer 1

The delimiter command is used by the client program to determine the limits of the SQL statement. It is (almost certainly) not seen by the server itself. Therefore, in Perl + DBI, you should simply omit the delimiters. Thus, the command you should execute is:

my $sql = qq{ 
    CREATE TRIGGER `hardware_last_status` BEFORE UPDATE
        ON `hardware` FOR EACH ROW BEGIN
                            IF NEW.status != OLD.status AND NEW.last_status = OLD.last_status THEN
                                SET NEW.last_status = OLD.status;
                            END IF;
                        END
};